Electrochemical cells are used for a variety of purposes. For example, electrochemical cells may be used for water treatment processes in order to produce two forms of altered water: reduced or alkaline water and oxidized or acidic water. Electrochemical cells may also be used to produce hypochlorite solutions or chlorine for bleaches, surface sanitizers and other disinfectants. The electrolysis of salt to generate chlorine is also well established. In addition, electrochemical cells are used for the conversion of sodium carbonate into sodium hydroxide. See e.g. U.S. Pat. No. 5,246,551.
Conventional electrolysis cells are equipped with at least an anode and a cathode and often have a dual structure in which the anode and cathode are separated by one or more membranes to divide the cells into chambers, including an anode chamber and a cathode chamber. A barrier membrane provides the advantage of preventing the products in the anode chamber from mixing with the products from the cathode chamber. Various electrolysis cells and methods for electrolyzing water for various purposes are disclosed, for example in U.S. Pat. Nos. 3,616,355, 4,062,754, 4,100,052, 4,761,208, 5,313,589, and 5,954,939. Depending upon the structure of an electrochemical cell, various effluents are generated.
On-site production of enhanced alkalinity products such as detergents are desirable, in order to decrease or eliminate the need to transport caustic products and/or diluted aqueous solutions of the caustic products which both increase the cost of transporting chemicals. In addition, the on-site production of enhanced alkalinity products significantly reduces the safety concerns associated with the transport and handling of highly alkaline cleaning compositions which present dangers due to the caustic nature of the chemicals capable of causing burns to exposed skin, particularly in the concentrated form. As the alkalinity of the compositions increases, the possible risk to workers also increases. Great care must therefore be taken to protect workers who handle highly alkaline cleaning compositions. As a result, there is a need to provide in situ methods of enhancing the alkalinity of detergents and cleaning compositions in order to reduce or alleviate these concerns.
Highly alkaline cleaning compositions provide the ability to clean in various applications. For example, alkaline cleaners are effective as grill and oven cleaners, ware wash detergents, laundry detergents, laundry presoaks, drain cleaners, hard surface cleaners, surgical instrument cleaners, transportation vehicle cleaning, dish wash presoaks, dish wash detergents, beverage machine cleaners, concrete cleaners, building exterior cleaners, metal cleaners, floor finish strippers, degreasers and burned-on soil removers. In a variety of these applications, cleaning compositions having a very high alkalinity are most desirable and efficacious. For example, floor stripping compositions for removal of floor finishes are most effective at a highly alkaline pH.
Accordingly, it is an objective of the invention to formulate improved methods and devices for in situ production of enhanced alkalinity through the conversion of bicarbonate, sesquicarbonate, or carbonate into caustic.
It is an objective of the invention to provide efficient and economic methods for electrochemical enhancement of alkalinity without coproduction of chlorine and acids.
It is a further objective of the invention to reduce the safety concerns and costs associated with transporting caustic products.